JP2003055653A - Method of manufacturing spherical phosphor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a phosphor which comprises a spherical particle having a controlled particle size and a narrow particle-size distribution, by a process comprising calcining at a lower temperature than in the conventional dry process. SOLUTION: An aqueous solution or suspension containing elements required for the composition of a desired phosphor is dispersed in a nonaqueous medium to prepare a W/O emulsion, which is then dehydrated to prepare a powder composed of a spherical particle as a phosphor precursor, and subsequently the powder is calcined in an oxidizing atmosphere or calcined and then reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a spherical phosphor that can be suitably used in a plasma display panel (PDP).

[0002]

2. Description of the Related Art A PDP is formed by pasting phosphors of three primary colors of light, blue, green and red, and applying them to a substrate,
The phosphor film is fired to form a thin film phosphor film, and the phosphor film is irradiated with vacuum ultraviolet rays to cause the phosphor to emit light.

Of the above phosphors, for example, the blue phosphor europium-activated barium magnesium aluminate is
Raw material mixed powder consisting of barium carbonate, magnesium oxide, aluminum oxide and europium oxide in a ratio corresponding to the composition of the phosphor, if necessary, together with the flux,
It can be obtained by reducing after firing.
However, in most cases, the phosphor obtained by this method consists of plate-like particles. Further, in order to obtain a phosphor having high crystallinity and high brightness, it is necessary to sinter the above raw material mixed powder at a high temperature, and thus the obtained phosphor has a remarkable aggregation between particles.

Further, for example, the manganese-activated zinc silicate of the green phosphor is prepared by melting raw material powder consisting of silicon oxide, zinc oxide and manganese carbonate in a proportion corresponding to the composition of the phosphor, if necessary. Although it can be obtained by firing with an agent, a high firing temperature is required in order to obtain high crystallinity and high brightness like the above-mentioned blue phosphor, and thus the obtained phosphor is almost In the case of No. 1, the particles consist of fused and irregularly shaped particles. As described above, it is impossible to obtain a spherical phosphor having a narrow distribution by the conventional dry method.

On the other hand, in order to improve the emission brightness of the phosphor film, it is necessary to optimally control the particle size of the phosphor and increase the packing density of the phosphor. However, the phosphor obtained by the above-mentioned dry method is agglomerated among particles or is sintered to be coarse particles, and cannot be highly filled in the phosphor film. Further, when using a strong crushing means to disperse the powder with high strength, there is a problem that the primary particles are crushed to generate fine particles, or the crystallinity of the phosphor is damaged and the brightness is lowered. .

Therefore, in order to solve such a problem, various methods for obtaining a phosphor composed of spherical particles have been proposed in the past ("Spherical phosphor" in the 23rd Plasma Display Technology Conference Material). (1999)).

More specifically, for example, Japanese Patent Laid-Open No. 2000-8
No. 7033 discloses that an aqueous solution containing a required element is prepared, and the droplet is introduced into a pyrolysis reaction furnace together with a carrier gas and heated to a temperature of 600 to 1900 ° C. while staying in the furnace. , Reheating at a temperature of 950 to 1450 ° C. to obtain a spherical phosphor is described.

In addition to these, various methods are known, but all of them require a step including firing at high temperature to obtain a phosphor having high crystallinity and high brightness. Thus, in the obtained phosphor, strong agglomeration between particles and mutual fusion are unavoidable.

As described above, heretofore, no method has been known for producing a spherical phosphor having a controlled particle size and a narrow particle size distribution without strong aggregation between particles or mutual fusion.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in conventional phosphors, and includes a step of firing at a lower temperature as compared with a conventional dry method. Therefore, it is an object of the present invention to provide a method for producing a phosphor having spherical particles having a controlled particle size and a narrow particle size distribution.

[0011]

According to the present invention, an aqueous solution or suspension containing the required elements in the composition ratio of the desired phosphor is dispersed in a non-aqueous medium to obtain a W / O type. After being made into an emulsion, this emulsion is dehydrated to obtain a powder consisting of spherical particles as a phosphor precursor, and then the powder is calcined in an oxidizing atmosphere, or calcined and then reduced. A method for manufacturing the above-mentioned spherical phosphor is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a phosphor according to the present invention is a W / O type emulsion in which an aqueous solution or suspension containing the required elements in the composition ratio of the phosphor is dispersed in a non-aqueous medium. After that, the emulsion is dehydrated to obtain a powder consisting of spherical particles as a phosphor precursor, and then the powder is calcined in an oxidizing atmosphere, or calcined and then reduced.

When preparing an aqueous solution or suspension containing the required elements in the composition ratio of the desired phosphor (hereinafter referred to as raw material aqueous solution), the raw materials for the respective elements are the final step. There is no particular limitation as long as it decomposes to form an oxide by firing in a certain oxidizing atmosphere or firing in a reducing atmosphere. Therefore, as a raw material of each element,
For example, oxides, hydroxides, nitrates, acetates, carbonates,
Halides, organic acid salts, etc. are appropriately used. When the raw material of the above element is insoluble or sparingly soluble in water, it may be dissolved in water using an acid or an alkali. Also, when a raw material aqueous solution is obtained using a metal as a starting material, the metal may be similarly dissolved in water using an acid or an alkali.

Further, according to the present invention, in the raw material aqueous liquid, each element may partially or wholly form an oxide or hydroxide sol, or form a gel. Good.

Such a sol or gel can be generally produced by adding an alkali to an aqueous solution of a metal salt, but it can also be produced by hydrolyzing a metal alkoxide. Particularly, according to the present invention, the sol obtained by the latter method is preferable from the viewpoint of the homogeneity inside the precursor particles.

According to the present invention, the raw material aqueous liquid may optionally contain a water-miscible organic solvent. Examples of such an organic solvent include methanol and ethanol.

After the raw material aqueous liquid has been prepared in this manner, it is dispersed as droplets in a non-aqueous medium in the presence of a surfactant by using an appropriate dispersing means to obtain a W / O type emulsion. To prepare.

The non-aqueous medium used in the present invention is not particularly limited as long as it has been conventionally used for the preparation of emulsions. For example, n-octene, isooctene, squalane, kerosene, etc. Aliphatic hydrocarbons, alicyclic hydrocarbons such as cyclooctane, cyclononane, and cyclodecane, toluene, ethylbenzene,
Aromatic hydrocarbons such as isopropylbenzene, cumene, mesitylene and tetralin, ethers such as butyl ether and isobutyl ether, halogenated hydrocarbons such as dichloropentane, natural oils such as mineral oil and animal and vegetable oils, hydrocarbon oils and esters Examples thereof include oils, ether oils, fluorine-containing lubricating oils, phosphorus-containing lubricating oils, silicon-containing lubricating oils, and other synthetic oils.

The surfactant used to prepare the emulsion is appropriately selected depending on the non-aqueous medium used. Thus, for example, without limitation, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, and other sorbitan fatty acid esters. And glycerin fatty acid esters such as glycerin monostearate and glycerin monooleate are preferably used.

The amount of the surfactant used may be appropriately selected depending on the W / O ratio in the emulsion, the required particle size and the like, and is not particularly limited, but is usually 20% by weight with respect to the emulsion. % Or less, preferably,
It is in the range of 0.5 to 15% by weight. Further, the W / O ratio in the emulsion depends on the amount and properties of the non-aqueous medium used, particularly the viscosity, and the properties of the surfactant used, especially the HLB value. Three
/ 2 to 1/10, preferably 1/1 to 1
/ 5, particularly preferably 1/3 to 1/5. However, in the present invention, the method for preparing an emulsion is not particularly limited to the above-exemplified method.

According to the present invention, after the emulsion is prepared in this way, the droplets in the emulsion are dehydrated and dried to form a powder consisting of spherical particles as a precursor of the target phosphor. To get

The average particle size and particle size distribution of such precursor particles and the phosphors obtained from them are as follows: droplet size (average particle size) and particle size distribution in emulsion, concentration of raw material aqueous liquid, etc. Can be adjusted accordingly. The size (average particle size) and particle size distribution of the droplets in the emulsion can be adjusted by the combination and the amount of the surfactants used, the type of disperser, the stirring speed of the disperser, and the like.

To dehydrate and dry the droplets in the emulsion, for example, a method of heating the emulsion under normal pressure or reduced pressure while gently stirring it, or dropping the emulsion in a heated non-aqueous medium while strongly stirring it Then, a method of dehydrating can be mentioned. Also, freeze-drying can be used.

According to the present invention, the powder is fired and oxidized in an oxidizing atmosphere, and then fired and reduced in a reducing atmosphere depending on the intended phosphor, thereby obtaining the object. The phosphor can be obtained as spherical particles.

To bake and oxidize the above precursor particles,
Usually, in air at a temperature of 1000 to 1900 ° C. for several hours,
Just heat. Also, depending on the target phosphor,
After this firing, 1000 to 1700 ° C. in a reducing atmosphere
It suffices to calcine and reduce at the temperature. As the reducing atmosphere, for example, a mixed atmosphere of hydrogen and nitrogen is used.

According to the present invention, since the emulsion having the raw material aqueous liquid as droplets is prepared, all the components for the target phosphor are present in the fine spherical droplets, and such an emulsion is formed. After dehydration and drying, a phosphor precursor is obtained as a powder consisting of spherical particles, and this is fired to obtain the desired phosphor. Therefore, according to the present invention, a phosphor having a uniform composition and a high spherical property can be obtained by firing at a lower temperature as compared with the conventional dry method.

The method of the present invention is not particularly limited, but for example, a spherical aluminate phosphor, for example, the general formula Ba _1-x Eu _x MgAl ₁₀ O ₁₇ (where x is 0). Or a spherical silicate phosphor, for example, a general formula Zn _y SiO ₄ : Mn (where y is 1. It is suitable for the production of the phosphor represented by the formula (0 to 2.0).

In the present invention, in such an aluminate phosphor, a part of Ba, Eu or Mg is formed by an alkaline earth element or a rare earth element such as Sr, Ca, La, Ce, Gd or Tb. It may be substituted.
Further, in the silicate phosphor, a part of Zn is Cd, C
It may be substituted with an element such as u or As.

According to the present invention, the phosphor thus obtained has a azimuthal average particle size in the range of 0.3 to 5.0 μm and a particle size d (Μm) and an equation V = 10 ⁻¹⁸ α _v d ³ representing the volume V (m ³ ) of the particle and an equation S = 10 ⁻¹² α _s representing α _v (volume shape factor) and surface area S (m ² ) in α _v d ³ .
The shape factor defined by the ratio α _s / α _v with α _s (surface shape factor) in d ² is 15 or less, and the quartile ratio (qu) is used for the particle size distribution measured by the laser diffraction particle size distribution measurement.
artile ratio) is 3.0 or less.

The above shape factor is the E. This is called the Rammler's shape factor, and is 6 for true spherical particles. For a particle, the particle size is d (μm), the volume is V (m ³ ), the surface area is S (m ² ), and the true density is ρ (g / c).
m ³ ), and the specific surface area is S _B (m ² / g), since V = 10 ⁻¹⁸ α _v d ³ = A / 10 ⁶ ρ for sample A (g), α _v = 10 ¹² A / ρd ³ . In addition, since S = 10 ⁻¹² α _s d ² = S _B A, α _s = 10 ¹² S _B A / d ² . Therefore, α _s / α _v = (S _B A / d ² ) / (A / ρd ³ ) = S _B
ρd

That is, the above-mentioned shape factors are the specific surface area S _B (m ² ) of the particles, the true density ρ (g / cm ³ ) and the particle size d (μ
m) and

Further, the quartile ratio means the total amount in the cumulative particle size distribution curve in laser diffraction type particle size distribution measurement, which is 1
When set to 00%, the particle size at the 75% cumulative distribution point is 2
A value divided by the particle size at the 5% cumulative distribution point, and when the particle size uniformity is high, that is, when the particle size distribution is narrow, the above value is close to 1, and when the particle size uniformity is low, that is, The above value becomes large when the particle size distribution is wide.

The spherical phosphor obtained according to the present invention preferably has a azimuthal average particle size in the range of 0.3 to 5.0 μm and a shape factor of 15 or less, as determined by scanning electron micrograph. With respect to the particle size distribution by laser diffraction type particle size distribution measurement, preferably,
The quartile ratio is 2.5 or less, and particularly preferably 2.0 or less. Thus, the spherical phosphor obtained by the present invention has a controlled particle size, a narrow particle size distribution, and high sphericity, so that the PDP film can be highly filled with the phosphor. Therefore, it is possible to obtain a phosphor film having high emission brightness.

[0034]

The present invention will be described below with reference to examples.
The present invention is not limited to these examples. In the following, the particle size distribution was measured as follows. Approximately 70 mL of a 0.025 wt% sodium hexametaphosphate aqueous solution was added with several tens of mg of the sample, and ultrasonic dispersion was performed. Then, using a laser diffraction type particle size distribution analyzer LA-500 manufactured by Horiba, Ltd., 0.025 wt. % Sodium hexametaphosphate aqueous solution as a dispersion medium, the particle size distribution of the sample was measured.

In the calculation of the shape factor, the specific surface area S _B was obtained by the nitrogen adsorption BET method, and the particle size d was obtained as the oriented average particle size in the scanning electron micrograph. In Examples 1 and 2, Ba _0.9 Eu _0.1
True density ρ (g / cm) of MgAl ₁₀ O ₁₇ (hexagonal system)
³ ) was determined as follows. That is, JCPDSCa
rds No. 26-163 to the lattice constant a (= 5.6
Cell volume V from 2Å) and c (= 22.64Å)
_C (Å ³ )

[0036]

[Equation 1]

On the other hand, the molecular weight M _w (= 703.4)
4), and since two molecules form a cell, N _A (=
As 6.02 × ¹⁰ 23 / mol) Avogadro's number, it is _{^{ρ = 2 × 10 24 M w}} / N A V c.

Example 1 5.94 g of aluminum metal was dissolved in an aqueous nitric acid solution containing 82.1 g of concentrated nitric acid and 0.2 L of water, and then 7.1 g of barium hydroxide octahydrate and 0.1 g of europium oxide were added to the aqueous solution. 39 g and basic magnesium carbonate 2.2 g were added and dissolved, and water was further added to make the total amount 400 mL. This is called W liquid.

Separately, 690 g of mineral oil and 69 g of sorbitan monooleate were mixed and stirred in a 1 L glass beaker to obtain a uniform mixture. This is called liquid O.

The above liquid O and liquid W were stirred with a stirrer for 30 minutes in a 2 L capacity glass beaker to prepare a W / O type emulsion. This is called liquid E.

Next, add 3 L of mineral oil to a 5 L glass beaker.
84 g was added and the temperature was raised to 140 to 160 ° C. with stirring. While maintaining this temperature, the above E
The liquid was gradually added dropwise to dehydrate the emulsion particles.
The obtained precipitate was separated by filtration, washed, and then air-dried to obtain a spherical precursor as a powder. As shown in the scanning electron micrograph of this powder in FIG. 1, the spherical precursor has a particle size of 0.5 to 3
It was composed of spherical particles of μm.

The spherical precursor was placed in an alumina crucible,
After calcination in air at 1200 ° C. for 2 hours, calcination in a reducing gas stream consisting of 95% nitrogen and 5% hydrogen for 2 hours at 1400 ° C. to reduce Ba _0.9 Eu _0.1 MgAl ₁₀
A blue phosphor represented by O ₁₇ was obtained. As shown in FIG. 2, a scanning electron micrograph of the phosphor thus obtained shows a particle size of 0.5 to 2.5 μm and a azimuth average particle size of 0.68.
It was composed of spherical particles of μm. The X-ray diffraction profile is shown in FIG. Further, the emission spectrum of the obtained phosphor has a main peak near 450 nm as shown in FIG.

As shown in FIG. 5, this phosphor has a narrow particle size distribution by laser diffraction and has an average particle size of 1.47 μm. The quartile ratio obtained from the cumulative particle size distribution curve of the particle size distribution data was 1.90.

Further, the true density of this phosphor ρ = 3.8 g /
cm ³ , specific surface area S _B = 2.14 m ² / g, particle size d =
Since it was 0.68 μm, the shape factor was 9.1 according to the above formula.

Example 2 13.8 g of aluminum isopropoxide, 1.55 g of barium acetate, 1.48 g of magnesium acetate tetrahydrate and 0.26 g of europium acetate were added to 0.5 L of water with stirring, and then acetic acid was added. Was added to adjust the pH to 4, and then the mixture was hydrolyzed for 1 hour to obtain an aqueous solution containing alumina sol. This is called W liquid.

Separately, 225 g of mineral oil and 23 g of sorbitan monooleate were mixed and stirred in a 500 mL beaker made of glass to obtain a uniform mixture. This is called liquid O.

The above liquid O and liquid W were stirred with a homomixer for 5 minutes in a 1 L glass beaker to prepare a W / O type emulsion. This is called liquid E.

Next, this emulsion was gradually heated under reduced pressure and heated at 80 ° C. for 1 hour for dehydration. The precipitate thus obtained was filtered off, washed and air dried to obtain a spherical precursor as a powder. As shown in the scanning electron micrograph of this powder, as shown in FIG. 6, it consisted of spherical particles having a particle size of 0.3 to 1.5 μm.

The above spherical precursor was placed in an alumina crucible,
After calcination in air at 1200 ° C. for 2 hours, calcination in a reducing gas stream consisting of 95% nitrogen and 5% hydrogen for 2 hours at 1400 ° C. to reduce Ba _0.9 Eu _0.1 MgAl ₁₀
A blue phosphor represented by O ₁₇ was obtained. As shown in FIG. 7, a scanning electron micrograph of the phosphor thus obtained has a particle size of 0.5 to 2.5 μm and a azimuth average particle size of 0.62.
It was composed of spherical particles of μm. Further, as shown in the emission spectrum of this phosphor, it has a main peak near 450 nm.

Further, this phosphor has an average particle size of 0.62 μm as shown in FIG. 9 in its laser diffraction particle size distribution, and the quartile ratio obtained from the cumulative particle size distribution curve of this particle size distribution data is It was 2.26.

The true density of this phosphor ρ = 3.8 g /
cm ³ , specific surface area S _B = 5.70 m ² / g, particle size d =
Since it was 0.58 μm, the shape factor was 12.6 according to the above formula.

Example 3 To 300 mL of water, 24.23 g of zinc nitrate hexahydrate and 1.38 g of manganese nitrate hexahydrate were added and dissolved. Tetraethoxysilane 9.98g was added to this, and it hydrolyzed at 80 degreeC overnight, it was made into a sol, and the suspension was obtained. It was cooled to room temperature. This is called W liquid.

Hereinafter, Example 1 was repeated except that this W liquid was used.
A spherical precursor was obtained as a powder in the same manner as in. This powder was put into an alumina crucible and fired in air at 1250 ° C. for 2 hours to obtain a green phosphor represented by Zn _1.7 SiO ₄ : Mn. A scanning electron micrograph of this phosphor is shown in FIG.
As shown in 0, it was composed of spherical particles having a particle size of 0.3 to 1.0 μm and a fixed orientation average particle size of 0.67 μm. The emission spectrum of this phosphor has a main peak near 525 nm, as shown in FIG.

Further, this phosphor has a narrow particle size distribution, as shown in its laser diffraction particle size distribution in FIG.
The average particle size is 0.59 μm. The quartile ratio obtained from the cumulative particle size distribution curve of this particle size distribution data was 1.88.

Regarding the above-mentioned phosphor, JCPDS Ca
rds No. According to 37-1485, Zn ₂ SiO
_Although it is described that ₄ is a rhombohedral crystal, a crystal angle is not described and a true density cannot be calculated.
Therefore, the average value was set to 4.1 g / cm ³ from the literature value (MELLOR'S COMPREHENSIVE
TREATISE ON INORGANIC AN
D THEORETICAL CHEMISTRY, V
ol. 6, p. 439, J. Lorenzen (4.1
1 g / cm ³ ), T.I. Thomson (3.935g /
cm ³ ), F.I. A. Genth (4.10 g / c
m ³ ), W. G. Mixter (4.11 to 4.16 g
/ Cm ³ ), C.I. H. Stone (4.132 to 4.1)
88 g / cm ³ ), A. Gorgeu (4.25 g / c
m ³ ), G.I. Stein (3.7 g / cm ³ ).

Therefore, the specific surface area S _B of this phosphor = 5.
Since the particle size was 32 m ² / g and the particle diameter d = 0.67 μm, the shape factor was 14.6 according to the above formula.

Example 4 Liquid W and liquid O were prepared in the same manner as in Example 1 and then 2 L
The above-mentioned two liquids were put into a polyethylene bottle having a capacity, and the bottle was sealed. Shake vigorously for 10 minutes to obtain solution E. Thereafter, a blue phosphor was obtained in the same manner as in Example 1.

This blue phosphor had an average particle size of 1.79 μm as determined by laser diffraction type particle size distribution measurement, and a quartile ratio of 1.95 determined from its cumulative particle size distribution curve.
In addition, since the true density ρ of this phosphor is 3.8 g / cm ³ , the specific surface area S _{B is} 3.21 m ² / g, and the particle diameter d is 1.19 μm, the shape factor is 14.5 according to the above formula. Met.

Example 5 In the same manner as in Example 1, a half amount of the W liquid of Example 1 and the same amount of the O liquid as in Example 1 were prepared and then placed in a stirrer in a 2 L capacity glass beaker. And mix the above two solutions.
A blue phosphor was obtained in the same manner as in Example 1.

This blue phosphor had an average particle size of 1.32 μm as determined by laser diffraction type particle size distribution measurement, and had a quartile ratio of 1.60 determined from its cumulative particle size distribution curve.
Further, since the true density ρ of this phosphor is 3.8 g / cm ³ , the specific surface area S _{B is} 3.22 m ² / g, and the particle diameter d is 1.01 μm, the shape factor is 12.4 according to the above formula. Met.

Example 6 In the example, barium hydroxide octahydrate of 7.1 g was replaced with barium hydroxide octahydrate of 4.7 g and strontium hydroxide octahydrate of 1.8 g. Ba _0.6 Sr _0.3 Eu _0.1 M in the same manner as in Example 1 except that the liquid and the O liquid were mixed using a stirrer for 10 minutes.
A blue phosphor represented by gAl ₁₀ O ₁₇ was obtained.

This blue phosphor had an average particle size of 1.27 μm as determined by laser diffraction type particle size distribution measurement, and a quartile ratio of 2.26 determined from its cumulative particle size distribution curve.
In addition, since the true density ρ of this phosphor is 3.8 g / cm ³ , the specific surface area S _{B is} 3.12 m ² / g, and the particle diameter d is 1.09 μm, the shape factor is 12.9 according to the above formula. Met.

Comparative Example 1 7.14 g of barium carbonate and 0.705 of europium oxide
g, magnesium oxide 1.61 g and high purity alumina 2
0.4 g was weighed out, and sodium sulfate as a flux was 1.76.
g and 0.105 g of aluminum fluoride, then 3 m
20 mL of m-zirconia beads was put in a container having a capacity of 100 mL, and mixed and pulverized in a planetary mill at 175 rpm for 20 minutes.

Then, the above beads were removed, the obtained powder was put into a crucible and baked in air at 1600 ° C. for 24 hours, then, in a reducing gas stream consisting of 95% nitrogen and 5% hydrogen,
Ba _0.9 Eu _0.1 Mg after reduction at 00 ° C. for 24 hours
A blue phosphor represented by Al ₁₀ O ₁₇ was obtained.

A scanning electron micrograph of this phosphor is shown in FIG.
As shown in 3, the plate-like particles had a particle size of 1 to 4 μm.
This phosphor has a main peak near 450 nm.

Comparative Example 2 13.26 g of zinc oxide, 5.76 g of silicon dioxide and 1.21 g of manganese carbonate (manganese content 43.6%) were weighed and 100 ml of 20 ml of 3 mm zirconia beads was weighed.
Put it in a container and mix it with a planetary mill at 175 rpm for 20 minutes.
It was crushed and mixed. Then, the beads were removed, the obtained powder was put into a crucible, and the powder was baked in air at 1400 ° C. for 3 hours to obtain Zn.
A green phosphor represented by _1.7 SiO ₄ : Mn was obtained.

A scanning electron micrograph of this phosphor is shown in FIG.
As shown in FIG. 4, it was composed of amorphous particles having a particle size of 1 to 20 μm and having advanced fusion. In addition, this phosphor is 52
It has a main peak near 5 nm.

[0068]

As described above, according to the present invention, by firing at a lower temperature as compared with the conventional dry method,
Uniform composition, controlled particle size and narrow particle size distribution, i.e.
Average particle size in the range of 0.3 to 5.0 μm and quartile ratio of 3.0 or less, preferably average particle size in the range of 1.0 to 2.5 μm and quartile ratio of 2.0 or less It is possible to obtain a spherical phosphor having a high spherical property. Therefore, such a phosphor can be highly filled in the phosphor film to provide a PDP with high brightness.

[Brief description of drawings]

1 is a scanning electron micrograph of precursor particles according to Example 1. FIG.

FIG. 2 is a scanning electron micrograph of the phosphor according to Example 1.

FIG. 3 is an X-ray diffraction profile of the phosphor according to Example 1.

FIG. 4 is an emission spectrum of the phosphor according to Example 1.

5 is a particle size distribution of the phosphor according to Example 1. FIG.

FIG. 6 is a scanning electron micrograph of precursor particles according to Example 2.

FIG. 7 is a scanning electron micrograph of the phosphor according to Example 2.

FIG. 8 is an emission spectrum of the phosphor according to Example 2.

FIG. 9 is a particle size distribution of the phosphor according to Example 2.

FIG. 10 is a scanning electron micrograph of the phosphor according to Example 3.

FIG. 11 is an emission spectrum of the phosphor according to Example 3.

FIG. 12 is a particle size distribution of the phosphor according to Example 3.

13 is a scanning electron micrograph of the phosphor according to Comparative Example 1. FIG.

FIG. 14 is a scanning electron micrograph of the phosphor according to Comparative Example 2.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinji Nakahara             5-1, Ebishimacho, Sakai City, Osaka Prefecture Sakai Chemical Industry             Within the corporation (72) Inventor Masaru Akita             5-1, Ebishimacho, Sakai City, Osaka Prefecture Sakai Chemical Industry             Within the corporation F-term (reference) 4H001 CA02 CA04 CF02 XA08 XA12                       XA13 XA14 XA30 XA56 XA63                       YA25

Claims (5)

[Claims] 1. An aqueous solution or suspension containing the required elements in the composition ratio of the desired phosphor is dispersed in a non-aqueous medium,
After forming a W / O type emulsion, this emulsion is dehydrated to obtain a powder consisting of spherical particles as a phosphor precursor, and then the powder is calcined in an oxidizing atmosphere, or calcined and then reduced. A method for producing a spherical phosphor, comprising: 2. A spherical phosphor is represented by the general formula Ba _1-x Eu _x MgAl ₁₀ O ₁₇ (where x is a number in the range of 0.01 to 0.5). Item 2. A method for producing a spherical phosphor according to Item 1. 3. The spherical phosphor is represented by the general formula Zn _y SiO ₄ : Mn (where y is a number in the range of 1.0 to 2.0). 1. A method for manufacturing a spherical phosphor of the above. 4. In the measurement with a scanning electron micrograph, the spherical phosphor has a azimuth average particle diameter in the range of 0.3 to 5.0 μm, and the particle diameter d (μm) and the volume V of the particle.
Α in the expression V = 10 ⁻¹⁸ α _v d ³ representing (m ³ ).
_v (volume shape factor) and surface area S (m ² ) representing the equation S =
^10-12 has a shape factor of 15 or less, which is defined by the ratio α _s (surface shape factor) to α _s / α _v in α _s d ^2, and with respect to the particle size distribution measured by laser diffraction particle size distribution measurement,
The method for producing a spherical phosphor according to claim 1, which has a quartile ratio of 3.0 or less. 5. The spherical phosphor has a azimuthal average particle size in the range of 0.3 to 1.5 μm, a shape factor of 15 or less, and a quartile ratio of 2.5 or less. A method for producing a spherical phosphor according to claim 4.